subject:(Gallium Nitride)

1. Hautakangas, Sami. Impurity Decoration of Native Vacancies in Ga and N Sublattices of Gallium Nitride.

Degree: 2005, Helsinki University of Technology

URL: http://lib.tkk.fi/Diss/2005/isbn9512276674/

►

The effects of impurity atoms as well as various growth methods to the formation of vacancy type defects in gallium nitride (GaN) have been studied… (more)

Subjects/Keywords: gallium nitride; positron annihilation; vacancy

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APA (6^th Edition):

Hautakangas, S. (2005). Impurity Decoration of Native Vacancies in Ga and N Sublattices of Gallium Nitride. (Thesis). Helsinki University of Technology. Retrieved from http://lib.tkk.fi/Diss/2005/isbn9512276674/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hautakangas, Sami. “Impurity Decoration of Native Vacancies in Ga and N Sublattices of Gallium Nitride.” 2005. Thesis, Helsinki University of Technology. Accessed June 16, 2019. http://lib.tkk.fi/Diss/2005/isbn9512276674/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hautakangas, Sami. “Impurity Decoration of Native Vacancies in Ga and N Sublattices of Gallium Nitride.” 2005. Web. 16 Jun 2019.

Vancouver:

Hautakangas S. Impurity Decoration of Native Vacancies in Ga and N Sublattices of Gallium Nitride. [Internet] [Thesis]. Helsinki University of Technology; 2005. [cited 2019 Jun 16]. Available from: http://lib.tkk.fi/Diss/2005/isbn9512276674/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hautakangas S. Impurity Decoration of Native Vacancies in Ga and N Sublattices of Gallium Nitride. [Thesis]. Helsinki University of Technology; 2005. Available from: http://lib.tkk.fi/Diss/2005/isbn9512276674/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Hong Kong

2. Zhang, Yiyun. GaN-based microdisk lasers on Si.

Degree: PhD, 2016, University of Hong Kong

URL: http://hdl.handle.net/10722/236587

► III-nitride compound semiconductors have emerged as indispensable materials for a wide range of optoelectronic devices. With wide and direct energy bandgaps, emissions from III-nitride semiconductors… (more)

▼ III-nitride compound semiconductors have emerged as indispensable materials for a wide range of optoelectronic devices. With wide and direct energy bandgaps, emissions from III-nitride semiconductors can cover the wavelength range from deep-ultraviolet to the near-infrared, making them ideal candidates for high-efficient light sources. Meanwhile, optical microcavities as significant building blocks of various optoelectronic devices have emerged as a distinct subject as well. High-quality microcavities are essential components for highly efficient micro-lasers via excellent optical confinement. Among them, microdisk lasers have drawn much attention owing to their high Q-factors and small mode-volumes as well as simple architectures. However, low-temperature operation, optically-pumping, and high thresholds are the existing obstacles ahead for the “state-of-art” nitride-based microdisk lasers stepping into real-life applications. Therefore, in this thesis, riding on the advantages of microsphere lithography (MSL) techniques, 2-μm GaN-based undercut microdisk cavities on Si with smooth sidewalls and excellent circularity have been demonstrated, which enables low-threshold lasing actions via whispering-gallery modes (WGMs) achieved at room temperature by reducing the energy loss at the disk edge, with Q-factors exceeding 1500 and a lasing threshold (Eth) as low as 8.43mJ/〖cm〗². These undercut GaN-on-Si microdisks are also providing a platform of research on the strain and optical coupling effects to the emission properties from these disk cavities. Strain-relaxation effects in 7-μm undercut GaN/InGaN microdisk cavities on Si have been further investigated in detail. The mitigation of biaxial tensile stress is found to be dependent on the contact areas between the Si posts and GaN microdisks. Quantum-confined Stark effect (QCSE) in the quantum wells (QWs) is reduced, leading to an enhancement of ~18.3% in its internal quantum efficiency (IQE). Light extraction is significantly enhanced in the suspended regions owing to reduced optical absorption at AlN/Si interface. Meanwhile, spectral blue-shifts of ~45.6 meV are observed at the microdisk edge. Such localization of strain relaxation can be exploited for precise strain-engineering in the microdisks. Further moving forwards to achieve electrically-pumped microdisk lasing on Si requires better control over the thread-dislocation densities and optimal thickness of the microdisk cavities for obtaining efficient optical gains and optical coupling with WGMs. Optically-pumped lasing properties of microdisk cavities with different thicknesses reveal a significant increase in spontaneous emission factors and an obvious reduction in Eth by reducing the disk thickness, which are meaningful to the cavity-design and epi-growth for demonstrating electrically-pumped microdisk lasing in the next step. GaN-based micro-dome cavities on Si have been demonstrated using a modified MSL technique, in which Fabry-Pérot resonances are totally ruled out. The WGMs blue-shift monotonously as…

Subjects/Keywords: Lasers; Gallium nitride; Semiconductors

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APA (6^th Edition):

Zhang, Y. (2016). GaN-based microdisk lasers on Si. (Doctoral Dissertation). University of Hong Kong. Retrieved from http://hdl.handle.net/10722/236587

Chicago Manual of Style (16^th Edition):

Zhang, Yiyun. “GaN-based microdisk lasers on Si.” 2016. Doctoral Dissertation, University of Hong Kong. Accessed June 16, 2019. http://hdl.handle.net/10722/236587.

MLA Handbook (7^th Edition):

Zhang, Yiyun. “GaN-based microdisk lasers on Si.” 2016. Web. 16 Jun 2019.

Vancouver:

Zhang Y. GaN-based microdisk lasers on Si. [Internet] [Doctoral dissertation]. University of Hong Kong; 2016. [cited 2019 Jun 16]. Available from: http://hdl.handle.net/10722/236587.

Council of Science Editors:

Zhang Y. GaN-based microdisk lasers on Si. [Doctoral Dissertation]. University of Hong Kong; 2016. Available from: http://hdl.handle.net/10722/236587

University of Hong Kong

3. Mak, Yick-hong, Giuseppe. Development of laser processes for nitride light-emitting diodes and its applications.

Degree: PhD, 2010, University of Hong Kong

URL: Mak, Y. G. [麥易康]. (2010). Development of laser processes for nitride light-emitting diodes and its applications. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4587982 ; http://dx.doi.org/10.5353/th_b4587982 ; http://hdl.handle.net/10722/134052

published_or_final_version

Electrical and Electronic Engineering

Doctoral

Doctor of Philosophy

Advisors/Committee Members: Lam, EYM, Choi, HW.

Subjects/Keywords: Light emitting diodes.; Gallium nitride.

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APA (6^th Edition):

Mak, Yick-hong, G. (2010). Development of laser processes for nitride light-emitting diodes and its applications. (Doctoral Dissertation). University of Hong Kong. Retrieved from Mak, Y. G. [麥易康]. (2010). Development of laser processes for nitride light-emitting diodes and its applications. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4587982 ; http://dx.doi.org/10.5353/th_b4587982 ; http://hdl.handle.net/10722/134052

Chicago Manual of Style (16^th Edition):

Mak, Yick-hong, Giuseppe. “Development of laser processes for nitride light-emitting diodes and its applications.” 2010. Doctoral Dissertation, University of Hong Kong. Accessed June 16, 2019. Mak, Y. G. [麥易康]. (2010). Development of laser processes for nitride light-emitting diodes and its applications. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4587982 ; http://dx.doi.org/10.5353/th_b4587982 ; http://hdl.handle.net/10722/134052.

MLA Handbook (7^th Edition):

Mak, Yick-hong, Giuseppe. “Development of laser processes for nitride light-emitting diodes and its applications.” 2010. Web. 16 Jun 2019.

Vancouver:

Mak, Yick-hong G. Development of laser processes for nitride light-emitting diodes and its applications. [Internet] [Doctoral dissertation]. University of Hong Kong; 2010. [cited 2019 Jun 16]. Available from: Mak, Y. G. [麥易康]. (2010). Development of laser processes for nitride light-emitting diodes and its applications. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4587982 ; http://dx.doi.org/10.5353/th_b4587982 ; http://hdl.handle.net/10722/134052.

Council of Science Editors:

Mak, Yick-hong G. Development of laser processes for nitride light-emitting diodes and its applications. [Doctoral Dissertation]. University of Hong Kong; 2010. Available from: Mak, Y. G. [麥易康]. (2010). Development of laser processes for nitride light-emitting diodes and its applications. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4587982 ; http://dx.doi.org/10.5353/th_b4587982 ; http://hdl.handle.net/10722/134052

University of Hong Kong

4. Zhang, Xuhui. GaN-based free-standing microdisks and nanostructures.

Degree: PhD, 2014, University of Hong Kong

URL: Zhang, X. [張旭輝]. (2014). GaN-based free-standing microdisks and nanostructures. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5334871 ; http://dx.doi.org/10.5353/th_b5334871 ; http://hdl.handle.net/10722/207202

► In this thesis, various micro- and nano-structures, fabricated by micro- and nanosphere lithography (NSL), were applied onto gallium nitride (GaN) based direct-bandgap semiconductors to develop… (more)

▼ In this thesis, various micro- and nano-structures, fabricated by micro- and nanosphere lithography (NSL), were applied onto gallium nitride (GaN) based direct-bandgap semiconductors to develop optical micro-cavities supporting whispering gallery mode (WGM) lasing action. This work includes three major sections. The first section introduces the novel nanostructures patterned by NSL and discusses their characterization. The second section elaborates the free-standing microdisk (FSD) cavities supporting WGM lasing. Last section provides an effective approach for optimizing FSD system by replacing the interface layer. Novel nanostructures for various applications are fabricated by NSL. First we developed and demonstrated a drop-on-demand method for fabricating twodimensional (2D) photonic crystal (PhC) arrays. Different geometries, such as nano-pillar and nano-cone, were obtained with variant etching parameters. The GaN PhCs comprising nano-pillar array with diameter of 200 nm were fabricated by different nano-patterning methods, NSL, focused ion beam lithography (FIB), and E-beam lithography (EBL). The surface morphologies and optical properties of fabricated structures were evaluated by various characterization techniques, including scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy, and transmission measurement. The NSL technique is regarded as a preferable approach in fabricating nanostructures. The FSD systems with diverse diameters of 1, 2, and 7 μm were prepared by laser lift-off (LLO) and microsphere lithography (MSL). The FSDs showed vertical and smooth sidewalls as confirmed by SEM images and served as an outstanding microcavities supporting WGM lasing. Optically pumped WGM lasing was obtained at room temperature for FSD systems. The lasing characteristics were fully studies. The thresholds were determined from the plots of PL peak intensity versus pumping energy density and the values were 5.01, 8.54, and 9.06 mJ/cm2 for FSDs with diameter of 1, 2, and 7 μm respectively. The remarkable quality (Q) factor of 2576 was achieved from 1 μm FSD. Anlysis for different thresholds and Q-factors were also discussed. By decreasing the FSD size, the number of lasing peaks is reduced to achieve single mode lasing due to the shrinkage of microdisk providing relatively large mode spacing. An elegant approach was conducted to improve the optical confinement in FSD system in the last section. The beneath layer, originally ITO, was replaced by a reflecting metallic Ni/Ag layer. The SEM images revealed that a thin FSD standing on metallic supporting layer was successfully fabricated. The WGM lasing was also obtained through optical pumping. Lasing mode centered at 430.0 nm has a threshold of 8.82 mJ/cm2 and a Q-factor of 1673. The free space range (FSR) was determined to be 3 nm. A comparison between FSD system with ITO layer and the one with NiAg layer indicated that the metallic layer can server as a reflecting layer and improved the optical confinement of the… Advisors/Committee Members: Choi, HW.

Subjects/Keywords: Nanostructures; Gallium nitride; Microstructure

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APA (6^th Edition):

Zhang, X. (2014). GaN-based free-standing microdisks and nanostructures. (Doctoral Dissertation). University of Hong Kong. Retrieved from Zhang, X. [張旭輝]. (2014). GaN-based free-standing microdisks and nanostructures. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5334871 ; http://dx.doi.org/10.5353/th_b5334871 ; http://hdl.handle.net/10722/207202

Chicago Manual of Style (16^th Edition):

Zhang, Xuhui. “GaN-based free-standing microdisks and nanostructures.” 2014. Doctoral Dissertation, University of Hong Kong. Accessed June 16, 2019. Zhang, X. [張旭輝]. (2014). GaN-based free-standing microdisks and nanostructures. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5334871 ; http://dx.doi.org/10.5353/th_b5334871 ; http://hdl.handle.net/10722/207202.

MLA Handbook (7^th Edition):

Zhang, Xuhui. “GaN-based free-standing microdisks and nanostructures.” 2014. Web. 16 Jun 2019.

Vancouver:

Zhang X. GaN-based free-standing microdisks and nanostructures. [Internet] [Doctoral dissertation]. University of Hong Kong; 2014. [cited 2019 Jun 16]. Available from: Zhang, X. [張旭輝]. (2014). GaN-based free-standing microdisks and nanostructures. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5334871 ; http://dx.doi.org/10.5353/th_b5334871 ; http://hdl.handle.net/10722/207202.

Council of Science Editors:

Zhang X. GaN-based free-standing microdisks and nanostructures. [Doctoral Dissertation]. University of Hong Kong; 2014. Available from: Zhang, X. [張旭輝]. (2014). GaN-based free-standing microdisks and nanostructures. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5334871 ; http://dx.doi.org/10.5353/th_b5334871 ; http://hdl.handle.net/10722/207202

Cornell University

5. Brown, Richard. Advanced Dielectrics For Gallium Nitride Power Electronics .

Degree: 2011, Cornell University

URL: http://hdl.handle.net/1813/33475

► This dissertation details the synthesis, characterization, and application of low-pressure chemical vapor deposited (LPCVD) Aluminum Silicon Nitride (Al x Siy Nz ) dielectrics to AlGaN/GaN… (more)

Subjects/Keywords: Gallium Nitride; hemt; Dielectric

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APA (6^th Edition):

Brown, R. (2011). Advanced Dielectrics For Gallium Nitride Power Electronics . (Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/33475

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Brown, Richard. “Advanced Dielectrics For Gallium Nitride Power Electronics .” 2011. Thesis, Cornell University. Accessed June 16, 2019. http://hdl.handle.net/1813/33475.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Brown, Richard. “Advanced Dielectrics For Gallium Nitride Power Electronics .” 2011. Web. 16 Jun 2019.

Vancouver:

Brown R. Advanced Dielectrics For Gallium Nitride Power Electronics . [Internet] [Thesis]. Cornell University; 2011. [cited 2019 Jun 16]. Available from: http://hdl.handle.net/1813/33475.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Brown R. Advanced Dielectrics For Gallium Nitride Power Electronics . [Thesis]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/33475

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

6. Malkowski, Thomas. High-Temperature Growth of Gallium Nitride Using the Ammonothermal Method with Ammonium Chloride Mineralizer.

Degree: 2016, University of California – eScholarship, University of California

URL: http://www.escholarship.org/uc/item/1tf7z2bm

► Gallium nitride (GaN) has become an important semiconductor for the optoelectronics and power electronics fields in the pursuit of high efficiency devices. However, the lack… (more)

▼ Gallium nitride (GaN) has become an important semiconductor for the optoelectronics and power electronics fields in the pursuit of high efficiency devices. However, the lack of a natural native GaN substrate has forced growth of GaN devices on foreign substrates such as sapphire, silicon carbide, and silicon. To further enhance efficiency and develop devices with longer lifetimes, the number of defects present in devices must be reduced. The development of a native GaN substrate of high crystalline quality would directly enable defect reduction. The ammonothermal method of GaN growth has shown significant promise as a technique for the production of high quality GaN crystals of industrially significant size (crystals on the order of centimeters in the largest dimension). The ammonothermal method is a solvothermal method that uses a mineralizer (here ammonium chloride) with supercritical ammonia to transport GaN from a source material from one temperature zone to grow a seed crystal in another temperature zone. High pressures, high temperatures, and the presence of a highly corrosive chemistry make development of an economical growth reactor challenging. This body of work outlines the development of a growth reactor capable of high temperature ammonothermal growth of GaN using ammonium chloride mineralizer.Initial development of the ammonothermal reactor required identification of suitable reactor materials. A materials stability study was conducted by exposing samples of materials to the ammonothermal environment and measuring mass loss as well as any chemical or mechanical changes that occurred. An Inconel 625 alloy reactor was employed, although the reactor itself was somewhat susceptible to corrosion from the ammonothermal environment. The study yielded a subset of materials that may be suitable for use as gaskets and other single use items which include niobium, molybdenum, titanium, vanadium, tungsten, gold, and platinum. Alloys of molybdenum and cobalt may also be useful. High strength titanium-zirconium-molybdenum (TZM) was also identified as a corrosion resistant material and was selected for reactor design.A TZM reactor was then designed and fabricated. Subsequent high pressure, high temperature tests indicated that TZM was essentially inert and growth of GaN crystals followed. All GaN growth was accomplished at or above 650°C using seed crystals grown by hydride vapor phase epitaxy. Seeds were characterized by micrometer measurements for growth thickness, x-ray diffraction (XRD) for crystalline quality, and secondary ion mass spectrometry (SIMS) for impurity concentrations. The growth quality appeared to match the seed quality as measured by XRD. Growth coloration ranged from slightly gray to green or yellow with growth rates up to 191 µm/day. Most seeds exhibited significant faceting at the edges of the sample, forming semipolar planes. SIMS was performed on a couple of samples which indicated oxygen concentrations of ~1018 cm¬-3.

Subjects/Keywords: Materials Science; ammonothermal; gallium nitride

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APA (6^th Edition):

Malkowski, T. (2016). High-Temperature Growth of Gallium Nitride Using the Ammonothermal Method with Ammonium Chloride Mineralizer. (Thesis). University of California – eScholarship, University of California. Retrieved from http://www.escholarship.org/uc/item/1tf7z2bm

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Malkowski, Thomas. “High-Temperature Growth of Gallium Nitride Using the Ammonothermal Method with Ammonium Chloride Mineralizer.” 2016. Thesis, University of California – eScholarship, University of California. Accessed June 16, 2019. http://www.escholarship.org/uc/item/1tf7z2bm.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Malkowski, Thomas. “High-Temperature Growth of Gallium Nitride Using the Ammonothermal Method with Ammonium Chloride Mineralizer.” 2016. Web. 16 Jun 2019.

Vancouver:

Malkowski T. High-Temperature Growth of Gallium Nitride Using the Ammonothermal Method with Ammonium Chloride Mineralizer. [Internet] [Thesis]. University of California – eScholarship, University of California; 2016. [cited 2019 Jun 16]. Available from: http://www.escholarship.org/uc/item/1tf7z2bm.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Malkowski T. High-Temperature Growth of Gallium Nitride Using the Ammonothermal Method with Ammonium Chloride Mineralizer. [Thesis]. University of California – eScholarship, University of California; 2016. Available from: http://www.escholarship.org/uc/item/1tf7z2bm

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Manchester

7. Jim, Lydia Man Wai. Physics of Gallium Nitride Quantum Wells.

Degree: 2019, University of Manchester

URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:319236

► In this thesis, studies performed on InGaN/GaN quantum well (QW) structures using photoluminescence (PL) spectroscopy are presented. Green light-emitting InGaN/GaN QW structures with a varying… (more)

▼ In this thesis, studies performed on InGaN/GaN quantum well (QW) structures using photoluminescence (PL) spectroscopy are presented. Green light-emitting InGaN/GaN QW structures with a varying number of QWs (1, 3, 5 & 10) were investigated with respect to the effect of QW number on internal quantum efficiency (IQE). 10 K transient PL measurements performed on the samples showed that the QW samples have different lifetimes. This suggests that there is a varying level of indium content amongst the samples, different average QW layer thickness between the samples and/or strain relaxation in the 10 QW sample. Comparing the 3 and 5 QW samples, which have similar lifetimes, the 300 K excitation power dependent IQE measurements performed on the samples shows that IQE increases with QW number; this can be attributed due to the increased recapture of escaped thermally excited carriers. Additionally, InGaN/GaN QWs with varying growth temperatures were studied with respect to their high energy band (HEB) and efficiency droop behaviour; the samples grown at higher growth temperatures have a lower defect density and this could affect the HEB and efficiency droop. The HEB is a recently reported feature on the high energy side of the typical emission peak in the PL spectra of InGaN/GaN QWs. 10 K excitation power dependent PL showed that the sample with the highest growth temperature exhibited efficiency droop at a higher excitation compared to the other samples; this may be because efficiency droop is influenced by defect-related recombination. 10 K time-resolved PL showed that the samples have similar HEB behaviour despite their different growth temperatures; monoexponential decay components and inflections which corresponded to the HEB were observed in the time decay measurements. 10 K excitation power varying time decay measurements performed across the PL spectra on one of the samples showed that the lifetime of the carriers at a given emission energy is constant at low carrier densities and decreases at high carrier densities; this reduction in lifetime occurred at a higher carrier density at higher PL emission energies. Advisors/Committee Members: MITCHELL, PETER PW, Binks, David, Mitchell, Peter.

Subjects/Keywords: InGaN; Gallium Nitride; Quantum Wells

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APA (6^th Edition):

Jim, L. M. W. (2019). Physics of Gallium Nitride Quantum Wells. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:319236

Chicago Manual of Style (16^th Edition):

Jim, Lydia Man Wai. “Physics of Gallium Nitride Quantum Wells.” 2019. Doctoral Dissertation, University of Manchester. Accessed June 16, 2019. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:319236.

MLA Handbook (7^th Edition):

Jim, Lydia Man Wai. “Physics of Gallium Nitride Quantum Wells.” 2019. Web. 16 Jun 2019.

Vancouver:

Jim LMW. Physics of Gallium Nitride Quantum Wells. [Internet] [Doctoral dissertation]. University of Manchester; 2019. [cited 2019 Jun 16]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:319236.

Council of Science Editors:

Jim LMW. Physics of Gallium Nitride Quantum Wells. [Doctoral Dissertation]. University of Manchester; 2019. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:319236

Indian Institute of Science

8. Yaddanapudi, G R Krishna. Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD.

Degree: 2016, Indian Institute of Science

URL: http://etd.iisc.ernet.in/handle/2005/2662 ; http://etd.ncsi.iisc.ernet.in/abstracts/3477/G27144-Abs.pdf

► Group III-Nitrides (GaN, InN & AlN) are considered one of the most important class of semiconducting materials after Si and GaAs. The excellent optical and… (more)

▼ Group III-Nitrides (GaN, InN & AlN) are considered one of the most important class of semiconducting materials after Si and GaAs. The excellent optical and electrical properties of these nitrides result in numerous applications in lighting, lasers, and high-power/high-frequency devices. Due to the lack of cheap bulk III- Nitride substrates, GaN based devices have been developed on foreign substrates like Si, sapphire and SiC. These technologies have been predominantly developed on the so called Ga-polarity epitaxial stacks with growth in the [0001] direction of GaN. It is this orientation that grows most easily on sapphire by metal organic chemical vapor deposition (MOCVD), the most common combination of substrate and deposition method used thus far. The opposite [000¯1] or N-polar orientation, very different in properties due to the lack of an inversion centre, offers several ad- vantages that could be exploited for better electronic and optoelectronic devices. However, its growth is more challenging and needs better understanding. The aim of the work reported in this dissertation was a systematic investigation of the relation between the various growth parameters which control polarity, surface roughness and mosaicity of GaN on non-miscut sapphire (0001) wafers for power electronics and lighting applications, with emphasis on the realization of N-polar epitaxial layers. GaN is grown on sapphire (0001) in a two-step process, which involves the deposition of a thin low temperature GaN nucleation layer (NL) on surface modified sapphire followed by the growth of high temperature device quality GaN epitaxial layer. The processing technique used is MOCVD. Various processing methods for synthesis of GaN layers are described with particular em- phasis on MOCVD method. The effect of ex situ cleaning followed by an in situ cleaning on the surface morphology of sapphire (0001) wafers is discussed. The characterization tools used in this dissertation for studying the chemical bond nature of nitrided sapphire surface and microstructural evolution (morphological and structural) of GaN layers are described in detail. The effect of nitridation temperature (TN) on structural transformation of non- miscut sapphire (0001) surface has been explored. The structural evolution of nitrided layers at different stages of their process like as grown stage and thermal annealing stage is investigated systematically. The chemical bond environment information of the nitrided layers have been examined by x-ray photoelectron spectroscopy (XPS). It is found that high temperature nitridation (TN ≥ 800 °C) results in an Al-N tetrahedral bond environment on sapphire surface. In contrast, low temperature nitridation (TN = 530 °C) results in a complex Al-O-N environment on sapphire surfaces. Microstructural evolution of low temperature GaN NLs has been studied at every stage of processing by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface roughness evolution and island size distribution of NLs measured from AFM… Advisors/Committee Members: Banerjee, Dipankar, Raghavan, Srinivasan.

Subjects/Keywords: Semiconductors; Nitrides; Gallium Nitride; N-Polar Gallium Nitride; Metal Organic Chemical Vapor Deposition (MOCVD); Galllium Nitride Growth; High Temperature Gallium Nitride; Low Temperature Gallium Nitride; GaN; Materials Engineering

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APA (6^th Edition):

Yaddanapudi, G. R. K. (2016). Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD. (Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ernet.in/handle/2005/2662 ; http://etd.ncsi.iisc.ernet.in/abstracts/3477/G27144-Abs.pdf

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Yaddanapudi, G R Krishna. “Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD.” 2016. Thesis, Indian Institute of Science. Accessed June 16, 2019. http://etd.iisc.ernet.in/handle/2005/2662 ; http://etd.ncsi.iisc.ernet.in/abstracts/3477/G27144-Abs.pdf.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Yaddanapudi, G R Krishna. “Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD.” 2016. Web. 16 Jun 2019.

Vancouver:

Yaddanapudi GRK. Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD. [Internet] [Thesis]. Indian Institute of Science; 2016. [cited 2019 Jun 16]. Available from: http://etd.iisc.ernet.in/handle/2005/2662 ; http://etd.ncsi.iisc.ernet.in/abstracts/3477/G27144-Abs.pdf.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Yaddanapudi GRK. Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD. [Thesis]. Indian Institute of Science; 2016. Available from: http://etd.iisc.ernet.in/handle/2005/2662 ; http://etd.ncsi.iisc.ernet.in/abstracts/3477/G27144-Abs.pdf

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Indian Institute of Science

9. Yaddanapudi, G R Krishna. Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD.

Degree: 2016, Indian Institute of Science

URL: http://hdl.handle.net/2005/2662

► Group III-Nitrides (GaN, InN & AlN) are considered one of the most important class of semiconducting materials after Si and GaAs. The excellent optical and… (more)

▼ Group III-Nitrides (GaN, InN & AlN) are considered one of the most important class of semiconducting materials after Si and GaAs. The excellent optical and electrical properties of these nitrides result in numerous applications in lighting, lasers, and high-power/high-frequency devices. Due to the lack of cheap bulk III- Nitride substrates, GaN based devices have been developed on foreign substrates like Si, sapphire and SiC. These technologies have been predominantly developed on the so called Ga-polarity epitaxial stacks with growth in the [0001] direction of GaN. It is this orientation that grows most easily on sapphire by metal organic chemical vapor deposition (MOCVD), the most common combination of substrate and deposition method used thus far. The opposite [000¯1] or N-polar orientation, very different in properties due to the lack of an inversion centre, offers several ad- vantages that could be exploited for better electronic and optoelectronic devices. However, its growth is more challenging and needs better understanding. The aim of the work reported in this dissertation was a systematic investigation of the relation between the various growth parameters which control polarity, surface roughness and mosaicity of GaN on non-miscut sapphire (0001) wafers for power electronics and lighting applications, with emphasis on the realization of N-polar epitaxial layers. GaN is grown on sapphire (0001) in a two-step process, which involves the deposition of a thin low temperature GaN nucleation layer (NL) on surface modified sapphire followed by the growth of high temperature device quality GaN epitaxial layer. The processing technique used is MOCVD. Various processing methods for synthesis of GaN layers are described with particular em- phasis on MOCVD method. The effect of ex situ cleaning followed by an in situ cleaning on the surface morphology of sapphire (0001) wafers is discussed. The characterization tools used in this dissertation for studying the chemical bond nature of nitrided sapphire surface and microstructural evolution (morphological and structural) of GaN layers are described in detail. The effect of nitridation temperature (TN) on structural transformation of non- miscut sapphire (0001) surface has been explored. The structural evolution of nitrided layers at different stages of their process like as grown stage and thermal annealing stage is investigated systematically. The chemical bond environment information of the nitrided layers have been examined by x-ray photoelectron spectroscopy (XPS). It is found that high temperature nitridation (TN ≥ 800 °C) results in an Al-N tetrahedral bond environment on sapphire surface. In contrast, low temperature nitridation (TN = 530 °C) results in a complex Al-O-N environment on sapphire surfaces. Microstructural evolution of low temperature GaN NLs has been studied at every stage of processing by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface roughness evolution and island size distribution of NLs measured from AFM… Advisors/Committee Members: Banerjee, Dipankar, Raghavan, Srinivasan.

Subjects/Keywords: Semiconductors; Nitrides; Gallium Nitride; N-Polar Gallium Nitride; Metal Organic Chemical Vapor Deposition (MOCVD); Galllium Nitride Growth; High Temperature Gallium Nitride; Low Temperature Gallium Nitride; GaN; Materials Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Yaddanapudi, G. R. K. (2016). Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD. (Thesis). Indian Institute of Science. Retrieved from http://hdl.handle.net/2005/2662

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Yaddanapudi, G R Krishna. “Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD.” 2016. Thesis, Indian Institute of Science. Accessed June 16, 2019. http://hdl.handle.net/2005/2662.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Yaddanapudi, G R Krishna. “Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD.” 2016. Web. 16 Jun 2019.

Vancouver:

Yaddanapudi GRK. Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD. [Internet] [Thesis]. Indian Institute of Science; 2016. [cited 2019 Jun 16]. Available from: http://hdl.handle.net/2005/2662.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Yaddanapudi GRK. Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD. [Thesis]. Indian Institute of Science; 2016. Available from: http://hdl.handle.net/2005/2662

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Anna University

10. Puviarasu P. Studies on the growth and characterisation of gallium nitride using chloride vapour phase epitaxy and the effect of swift heavy ion irradiations on gallium nitride epilayers;.

Degree: Studies on the growth and characterisation of gallium nitride using chloride vapour phase epitaxy and the effect of swift heavy ion irradiations on gallium nitride epilayers, 2014, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/24564

►

Group III nitrides such as Indium Nitride Gallium Nitride and Aluminium Nitride are currently the most challenging and technologically important materials which have the potential… (more)

Subjects/Keywords: Aluminium nitride; Chloride vapour phase epitaxy; Epitaxial techniques; Gallium nitride; Gallium nitride epilayers; Indium nitride; Science and humanities

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APA (6^th Edition):

P, P. (2014). Studies on the growth and characterisation of gallium nitride using chloride vapour phase epitaxy and the effect of swift heavy ion irradiations on gallium nitride epilayers;. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/24564

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

P, Puviarasu. “Studies on the growth and characterisation of gallium nitride using chloride vapour phase epitaxy and the effect of swift heavy ion irradiations on gallium nitride epilayers;.” 2014. Thesis, Anna University. Accessed June 16, 2019. http://shodhganga.inflibnet.ac.in/handle/10603/24564.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

P, Puviarasu. “Studies on the growth and characterisation of gallium nitride using chloride vapour phase epitaxy and the effect of swift heavy ion irradiations on gallium nitride epilayers;.” 2014. Web. 16 Jun 2019.

Vancouver:

P P. Studies on the growth and characterisation of gallium nitride using chloride vapour phase epitaxy and the effect of swift heavy ion irradiations on gallium nitride epilayers;. [Internet] [Thesis]. Anna University; 2014. [cited 2019 Jun 16]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/24564.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

P P. Studies on the growth and characterisation of gallium nitride using chloride vapour phase epitaxy and the effect of swift heavy ion irradiations on gallium nitride epilayers;. [Thesis]. Anna University; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/24564

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Anna University

11. Suresh kumar V. Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;.

Degree: Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers, 2015, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/41814

►

Gallium nitride GaN is one of the most promising materials newlineamong group III nitrides because its bandgap of 34 eV makes it the best newlinecandidate… (more)

Subjects/Keywords: gallium nitride; nanostructures; science and humanities

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

V, S. k. (2015). Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/41814

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

V, Suresh kumar. “Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;.” 2015. Thesis, Anna University. Accessed June 16, 2019. http://shodhganga.inflibnet.ac.in/handle/10603/41814.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

V, Suresh kumar. “Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;.” 2015. Web. 16 Jun 2019.

Vancouver:

V Sk. Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;. [Internet] [Thesis]. Anna University; 2015. [cited 2019 Jun 16]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/41814.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

V Sk. Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;. [Thesis]. Anna University; 2015. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/41814

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

12. Vais, Abhitosh. Physical simulation of GaN based HEMT.

Degree: 2012, Chalmers University of Technology

URL: http://studentarbeten.chalmers.se/publication/162773-physical-simulation-of-gan-based-hemt

► Recent improvements in the understanding and fabrication of GaN have led to its application in high frequency communication and high voltage switching systems. Requirement for… (more)

▼ Recent improvements in the understanding and fabrication of GaN have led to its application in high frequency communication and high voltage switching systems. Requirement for operation at even higher frequency and voltages is driving the research currently on design of GaN based devices which can operate at frequencies above 30 GHz and voltages up to 100 V. Reliability issues with GaN based devices operating in such conditions and lack of understanding of various phenomena are some of the factors hindering their widespread commercial development. There is a need to understand the device operation by developing a simulation model, as close to reality as possible, which could be, further, used to optimize the device design for high frequency and power operation. Recent improvements in the understanding and fabrication of GaN have led to its application in high frequency communication and high voltage switching systems. Requirement for operation at even higher frequency and voltages is driving the research currently on design of GaN based devices which can operate at frequencies above 30 GHz and voltages up to 100 V. Reliability issues with GaN based devices operating in such conditions and lack of understanding of various phenomena are some of the factors hindering their widespread commercial development. There is a need to understand the device operation by developing a simulation model, as close to reality as possible, which could be, further, used to optimize the device design for high frequency and power operation. This thesis work reports the design and development of a physical simulation model of AlGaN/GaN High Electron Mobility Transistor (HEMT) using commercial software (Synopsys, Sentaurus TCAD). The model is calibrated against measurement data. The results show a close matching with measured data, although some discrepancies have been found in the linear region of DC operation and high frequency regime of AC analysis. It is observed that trap density and their energy level (surface and bulk) play an important role in device characteristics. Effects of including quantum calculations in the model are analyzed. Various methods to improve the operating frequency have been investigated. The results show that by tuning the drain to gate distance, gate length and AlGaN thickness, AC characteristics can be improved significantly (fmax > 150 GHz). The influence of changing the epitaxial layer structure (adding more layers) on the device's AC characteristics is analysed to find an optimum design for high frequency applications.

Subjects/Keywords: Simulation; Gallium Nitride; High Electron Mobility Transistor

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APA (6^th Edition):

Vais, A. (2012). Physical simulation of GaN based HEMT. (Thesis). Chalmers University of Technology. Retrieved from http://studentarbeten.chalmers.se/publication/162773-physical-simulation-of-gan-based-hemt

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Vais, Abhitosh. “Physical simulation of GaN based HEMT.” 2012. Thesis, Chalmers University of Technology. Accessed June 16, 2019. http://studentarbeten.chalmers.se/publication/162773-physical-simulation-of-gan-based-hemt.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Vais, Abhitosh. “Physical simulation of GaN based HEMT.” 2012. Web. 16 Jun 2019.

Vancouver:

Vais A. Physical simulation of GaN based HEMT. [Internet] [Thesis]. Chalmers University of Technology; 2012. [cited 2019 Jun 16]. Available from: http://studentarbeten.chalmers.se/publication/162773-physical-simulation-of-gan-based-hemt.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Vais A. Physical simulation of GaN based HEMT. [Thesis]. Chalmers University of Technology; 2012. Available from: http://studentarbeten.chalmers.se/publication/162773-physical-simulation-of-gan-based-hemt

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Alberta

13. von Hauff, Peter A. Metal Oxide Processing on Gallium Nitride and Silino.

Degree: MS, Department of Electrical and Computer Engineering, 2012, University of Alberta

URL: https://era.library.ualberta.ca/files/pz50gw42f

► III-V Nitrides are intriguing semiconductors for high-power RF amplifiers and other applications. Gallium Nitride has become popular for mm-HFETs due to its material properties. The… (more)

Subjects/Keywords: Atomic Layer Depostion; metal oxides; Gallium Nitride

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APA (6^th Edition):

von Hauff, P. A. (2012). Metal Oxide Processing on Gallium Nitride and Silino. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/pz50gw42f

Chicago Manual of Style (16^th Edition):

von Hauff, Peter A. “Metal Oxide Processing on Gallium Nitride and Silino.” 2012. Masters Thesis, University of Alberta. Accessed June 16, 2019. https://era.library.ualberta.ca/files/pz50gw42f.

MLA Handbook (7^th Edition):

von Hauff, Peter A. “Metal Oxide Processing on Gallium Nitride and Silino.” 2012. Web. 16 Jun 2019.

Vancouver:

von Hauff PA. Metal Oxide Processing on Gallium Nitride and Silino. [Internet] [Masters thesis]. University of Alberta; 2012. [cited 2019 Jun 16]. Available from: https://era.library.ualberta.ca/files/pz50gw42f.

Council of Science Editors:

von Hauff PA. Metal Oxide Processing on Gallium Nitride and Silino. [Masters Thesis]. University of Alberta; 2012. Available from: https://era.library.ualberta.ca/files/pz50gw42f

University of Colorado

14. Montague, Joshua R. As-Grown Gallium Nitride Nanowire Electromechanical Resonators.

Degree: PhD, Physics, 2013, University of Colorado

URL: http://scholar.colorado.edu/phys_gradetds/74

► Technological development in recent years has led to a ubiquity of micro- and nano-scale electromechanical devices. Sensors for monitoring temperature, pressure, mass, etc., are… (more)

▼ Technological development in recent years has led to a ubiquity of micro- and nano-scale electromechanical devices. Sensors for monitoring temperature, pressure, mass, etc., are now found in nearly all electronic devices at both the industrial and consumer levels. As has been true for integrated circuit electronics, these electromechanical devices have continued to be scaled down in size. For many nanometer-scale structures with large surface-to-volume ratio, dissipation (energy loss) becomes prohibitively large causing a decreasing sensitivity with decreasing sensor size. In this work, gallium nitride (GaN) nanowires are investigated as singly-clamped (cantilever) mechanical resonators with typical mechanical quality factors, Q (equal to the ratio of resonance frequency to peak full-width-at-half-maximum-power) and resonance frequencies, respectively, at or above 30,000, and near 1 MHz. These Q values {in vacuum at room temperature{ indicate very low levels of dissipation; they are essentially the same as those for bulk quartz crystal resonators that form the basis of simple clocks and mass sensors. The GaN nanowires have lengths and diameters, respectively, of approximately 15 micrometers and hundreds of nanometers. As-grown GaN nanowire Q values are larger than other similarly-sized, bottom-up, cantilever resonators and this property makes them very attractive for use as resonant sensors. We demonstrate the capability of detecting sub-monolayer levels of atomic layer deposited (ALD) films, and the robust nature of the GaN nanowires structure that allows for their 'reuse' after removal of such layers. In addition to electron microscope-based measurement techniques, we demonstrate the successful capacitive detection of a single nanowire using microwave homodyne reflectometry. This technique is then extended to allow for simultaneous measurements of large ensembles of GaN nanowires on a single sample, providing statistical information about the distribution of individual nanowire properties. We observe nanowire-to-nanowire variations in the temperature dependence of GaN nanowire resonance frequency and in the observed mechanical dissipation. We also use this ensemble measurement technique to demonstrate unique, very low-loss resonance behavior at low temperatures. The low dissipation (and corresponding large Q values) observed in as-grown GaN nanowires also provides a unique opportunity for studying fundamental energy loss mechanisms in nano-scale objects. With estimated mass sensitivities on the level of zeptograms (10^-²¹ g) in a one second averaging time, GaN nanowires may be a significant addition to the field of resonant sensors and worthy of future research and device integration. Advisors/Committee Members: Charles Rogers, Victor M. Bright, Cindy Regal, Kyle McElroy, Daniel Dessau.

Subjects/Keywords: dissipation; gallium nitride; mems; nanowire; resonator; Physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Montague, J. R. (2013). As-Grown Gallium Nitride Nanowire Electromechanical Resonators. (Doctoral Dissertation). University of Colorado. Retrieved from http://scholar.colorado.edu/phys_gradetds/74

Chicago Manual of Style (16^th Edition):

Montague, Joshua R. “As-Grown Gallium Nitride Nanowire Electromechanical Resonators.” 2013. Doctoral Dissertation, University of Colorado. Accessed June 16, 2019. http://scholar.colorado.edu/phys_gradetds/74.

MLA Handbook (7^th Edition):

Montague, Joshua R. “As-Grown Gallium Nitride Nanowire Electromechanical Resonators.” 2013. Web. 16 Jun 2019.

Vancouver:

Montague JR. As-Grown Gallium Nitride Nanowire Electromechanical Resonators. [Internet] [Doctoral dissertation]. University of Colorado; 2013. [cited 2019 Jun 16]. Available from: http://scholar.colorado.edu/phys_gradetds/74.

Council of Science Editors:

Montague JR. As-Grown Gallium Nitride Nanowire Electromechanical Resonators. [Doctoral Dissertation]. University of Colorado; 2013. Available from: http://scholar.colorado.edu/phys_gradetds/74

Anna University

15. Munawar Basha S. Investigations on the magnetic properties of doped gallium nitride ion irradiation studies and nanostructure growth;.

Degree: 2014, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/14542

►

Gallium nitride (GaN) is by far more extensively studied than the newlineother III-nitrides because of its technological status. It has a wide direct band newlinegap… (more)

▼

Gallium nitride (GaN) is by far more extensively studied than the newlineother III-nitrides because of its technological status. It has a wide direct band newlinegap of 3.4 eV, thus making it suitable candidate for devices operating in blue newlineto ultra violet region of the electromagnetic spectrum. It is mainly used in newlinelight emitting diodes (LEDs), laser diodes and in detectors. Electronic devices newlinerealized in GaN operate at high power and at high temperatures. Recently, it newlinehas found application in the field of Spintronics with the controlled doping of newlinetransition metal dopants in GaN. Investigations have been carried out to study the ferromagnetic newlineproperties of transition metal (TM) doped wurtzite GaN from first principle newlinecalculations using Tight Binding Linear Muffin-tin Orbital (TBLMTO) newlinemethod within the density functional theory. The structural and optical studies were newlineevaluated using X-ray diffractometer and Photoluminescence measurements. newlineMagnetic properties of the synthesized samples have been evaluated with newlinesuperconducting quantum interface device measurements. Magnetic properties of the synthesized samples have been newlineevaluated with superconducting quantum interface device measurements. The newlineobserved results are correlated with the theoretical studies. The morphology of these nanostructures newlinewas studied using high resolution scanning electron microscope. X-ray newlinediffraction and micro-Raman spectroscopy measurements confirmed that the newlinegrown GaN nanostructures are of hexagonal wurtzite structure without any newlineadditional oxide phase. The emission properties of these nanostructures have newlinebeen investigated using Photoluminescence. newlineThe results of these investigations have been published in newlineinternational journals and also presented in several national and international newlineconferences newline newline

Advisors/Committee Members: Kumar, J..

Subjects/Keywords: Gallium nitride; magnetic; ion irradiation; nanostructure

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APA (6^th Edition):

S, M. B. (2014). Investigations on the magnetic properties of doped gallium nitride ion irradiation studies and nanostructure growth;. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/14542

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

S, Munawar Basha. “Investigations on the magnetic properties of doped gallium nitride ion irradiation studies and nanostructure growth;.” 2014. Thesis, Anna University. Accessed June 16, 2019. http://shodhganga.inflibnet.ac.in/handle/10603/14542.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

S, Munawar Basha. “Investigations on the magnetic properties of doped gallium nitride ion irradiation studies and nanostructure growth;.” 2014. Web. 16 Jun 2019.

Vancouver:

S MB. Investigations on the magnetic properties of doped gallium nitride ion irradiation studies and nanostructure growth;. [Internet] [Thesis]. Anna University; 2014. [cited 2019 Jun 16]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/14542.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

S MB. Investigations on the magnetic properties of doped gallium nitride ion irradiation studies and nanostructure growth;. [Thesis]. Anna University; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/14542

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Anna University

16. Suresh kumar V. Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;.

Degree: Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers, 2015, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/34219

►

Gallium nitride GaN is one of the most promising materials newlineamong group III nitrides because its bandgap of 34 eV makes it the best newlinecandidate… (more)

Subjects/Keywords: gallium nitride; ion irradiation; science and humanities

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

V, S. k. (2015). Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/34219

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

V, Suresh kumar. “Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;.” 2015. Thesis, Anna University. Accessed June 16, 2019. http://shodhganga.inflibnet.ac.in/handle/10603/34219.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

V, Suresh kumar. “Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;.” 2015. Web. 16 Jun 2019.

Vancouver:

V Sk. Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;. [Internet] [Thesis]. Anna University; 2015. [cited 2019 Jun 16]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/34219.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

V Sk. Growth and characterisation of gallium nitride nanostructures and investigations on the effect of ion irradiation on mocvd grown gallium nitride epilayers;. [Thesis]. Anna University; 2015. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/34219

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Hong Kong

17. Wang, Xianghua. Design and laser fabrication of GaN/sapphire light-emitting diodes.

Degree: PhD, 2010, University of Hong Kong

URL: Wang, X. [王向华]. (2010). Design and laser fabrication of GaN/sapphire light-emitting diodes. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4514307 ; http://dx.doi.org/10.5353/th_b4514307 ; http://hdl.handle.net/10722/131792

published_or_final_version

Electrical and Electronic Engineering

Doctoral

Doctor of Philosophy

Advisors/Committee Members: Lai, PT, Choi, HW.

Subjects/Keywords: Sapphires.; Gallium nitride.; Light emitting diodes.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, X. (2010). Design and laser fabrication of GaN/sapphire light-emitting diodes. (Doctoral Dissertation). University of Hong Kong. Retrieved from Wang, X. [王向华]. (2010). Design and laser fabrication of GaN/sapphire light-emitting diodes. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4514307 ; http://dx.doi.org/10.5353/th_b4514307 ; http://hdl.handle.net/10722/131792

Chicago Manual of Style (16^th Edition):

Wang, Xianghua. “Design and laser fabrication of GaN/sapphire light-emitting diodes.” 2010. Doctoral Dissertation, University of Hong Kong. Accessed June 16, 2019. Wang, X. [王向华]. (2010). Design and laser fabrication of GaN/sapphire light-emitting diodes. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4514307 ; http://dx.doi.org/10.5353/th_b4514307 ; http://hdl.handle.net/10722/131792.

MLA Handbook (7^th Edition):

Wang, Xianghua. “Design and laser fabrication of GaN/sapphire light-emitting diodes.” 2010. Web. 16 Jun 2019.

Vancouver:

Wang X. Design and laser fabrication of GaN/sapphire light-emitting diodes. [Internet] [Doctoral dissertation]. University of Hong Kong; 2010. [cited 2019 Jun 16]. Available from: Wang, X. [王向华]. (2010). Design and laser fabrication of GaN/sapphire light-emitting diodes. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4514307 ; http://dx.doi.org/10.5353/th_b4514307 ; http://hdl.handle.net/10722/131792.

Council of Science Editors:

Wang X. Design and laser fabrication of GaN/sapphire light-emitting diodes. [Doctoral Dissertation]. University of Hong Kong; 2010. Available from: Wang, X. [王向华]. (2010). Design and laser fabrication of GaN/sapphire light-emitting diodes. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4514307 ; http://dx.doi.org/10.5353/th_b4514307 ; http://hdl.handle.net/10722/131792

University of Hong Kong

18. 王銘正; Wang, Mingzheng. Optical studies of exciton-phonon coupling in nonpolar plane GaN.

Degree: M. Phil., 2017, University of Hong Kong

URL: http://hdl.handle.net/10722/249254

► Optical studies of nonpolar plane GaN substrates with emphasis on exciton-phonon coupling were carried carefully. These substrates were grown via HVPE method and had a… (more)

▼ Optical studies of nonpolar plane GaN substrates with emphasis on exciton-phonon coupling were carried carefully. These substrates were grown via HVPE method and had a good quality which enable us to distinguish diverse exciton lines and therefor have a profounder understanding of the exciton-phonon coupling process. It is widely believed that nonpolar GaN is one of the ultimate solutions for producing LEDs and HEMTs. Its excellent optical and electric properties take them an invincible lead in industries. Here, in this thesis, we use PL spectroscopy and Raman spectroscopy to study these samples. Temperature dependent PL spectra were carried with two different polarities of laser. The zero phonon lines of m-, a- and c-plane GaN were well resolved at low temperatures. For all samples, the dominated near band edge emission comprised free exciton transitions, donor bound electron transitions and an abnormal line. The binding energy of A-type exciton is estimated to 22 meV which is in a good agreement with theoretical one. B-type exciton transition is also resolved and found a strong polarity dependence on FXB. There are two kinds of donor bound excitons observed in PL spectra, which are A- and B-type free excitons bounded to neutral donors (Si on Ga site) independently. An abnormal line Ix is observed at the lower energy side of D0X whose origin is still under debate. TES transitions can be used to calculate the binding energy of bound exciton, in which radiative recombination leaves an excited electron on donor. By taking PL spectra measurement in various temperature, we know that Ix rapidly quenches, and there is an alteration of bound excitons to free excitons. Then, the attention was directed on the exciton-phonon coupling process. Detailed luminescence spectra were further investigated for corresponding LO-phonon replicas. The line shape and intensity of phonon-assisted emission is full of information. We use several theoretical models to give a reasonable explanation on the exciton-phonon coupling. We started with Huang-Rhys factor which characterizes the coupling strength of excitons and phonons. We can calculate the S factor of different transitions. Especially, B-type exciton shows a weak coupling strength, which can be theoretical attributed to its light effective mass. From the model proposed by Segall and Mahan, we can see the line shape of emission lines with phonon participation will reflect the Maxwell-Boltzmann distribution of the free exciton kinetic energy. A formula to describe this process was proposed and used to check experimental result immediately. It turns out that the Segall Mahan model runs very well for free exciton. Another model proposed by Hopfield was used to check donor bound exciton transition, moreover, a MBO model which propose a new phonon bath mode is also given. These two models somehow play a complementary role in investigation of exciton-phonon coupling. A well-defined oscillatory feature located in Fano resonance part was found in the low-temperature PL spectra of nonpolar… Advisors/Committee Members: Xu, S.

Subjects/Keywords: Optical properties - Gallium nitride; Electron-phonon interactions

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

王銘正; Wang, M. (2017). Optical studies of exciton-phonon coupling in nonpolar plane GaN. (Masters Thesis). University of Hong Kong. Retrieved from http://hdl.handle.net/10722/249254

Chicago Manual of Style (16^th Edition):

王銘正; Wang, Mingzheng. “Optical studies of exciton-phonon coupling in nonpolar plane GaN.” 2017. Masters Thesis, University of Hong Kong. Accessed June 16, 2019. http://hdl.handle.net/10722/249254.

MLA Handbook (7^th Edition):

王銘正; Wang, Mingzheng. “Optical studies of exciton-phonon coupling in nonpolar plane GaN.” 2017. Web. 16 Jun 2019.

Vancouver:

王銘正; Wang M. Optical studies of exciton-phonon coupling in nonpolar plane GaN. [Internet] [Masters thesis]. University of Hong Kong; 2017. [cited 2019 Jun 16]. Available from: http://hdl.handle.net/10722/249254.

Council of Science Editors:

王銘正; Wang M. Optical studies of exciton-phonon coupling in nonpolar plane GaN. [Masters Thesis]. University of Hong Kong; 2017. Available from: http://hdl.handle.net/10722/249254

Hong Kong University of Science and Technology

19. Yuan, Li. Process modeling and device technology of GaN normally-off power transistors.

Degree: 2011, Hong Kong University of Science and Technology

URL: https://doi.org/10.14711/thesis-b1146196 ; http://repository.ust.hk/ir/bitstream/1783.1-7195/1/th_redirect.html

► The wide bandgap GaN-based transistors are attractive for power electronics applications owing to the superior intrinsic properties of the materials. In addition to the breakdown… (more)

▼ The wide bandgap GaN-based transistors are attractive for power electronics applications owing to the superior intrinsic properties of the materials. In addition to the breakdown electric-field that is one order of magnitude higher than the mainstream semiconductor silicon, GaN-based heterostructrues (e.g. AlGaN/GaN) enhanced by spontaneous and piezoelectric polarization effects can yield a two-dimensional electron gas (2DEG) channel with a high sheet charge concentration and high electron mobility, both of which lead to low ON-state resistance. On the other hand, the high density 2DEG also presents the conventional AlGaN/GaN high electron mobility transistors (HEMTs) as depletion-mode transistors with a negative threshold voltage (Vth). For simpler circuit configuration and inherent fail-safe operation, normally-off GaN based HEMTs with positive threshold voltage are highly desired in modern power electronics systems. This thesis is focused on the process modeling and device technology of normally-off GaN power transistors. A process based on fluorine plasma ion implantation has been recently developed for achieving a robust control of the threshold voltage of AlGaN/GaN HEMTs, and is emerging as one of the most promising technologies for normally-off GaN power devices. To understand the underlying physical mechanisms of this process and also provide tools for process optimization, an atomistic hybrid molecular dynamics (MD)/kinetic Monte Carlo (KMC) model is developed for modeling the implantation and the subsequent annealing/diffusion behavior of the fluorine ions in AlGaN/GaN heterostructures. The MD simulation reveals the F distribution profiles and the corresponding defect profiles. Most importantly, the potential energy profiles of fluorine ions in the III-nitride material system are calculated for the first time, and the results fundamentally explained the stability of fluorine ions in AlGaN/GaN heterostructrues. Based on the results from the MD simulation, the diffusion process is modeled with KMC method, and the modeling results are validated by the secondary-ion-mass-spectrum (SIMS) measurement. The buffer leakage current is a common challenge being faced by the existing technologies of normally-off GaN power transistors due to the lack of high-quality blocking junctions in the leakage current path. To address this issue, a novel AlGaN/GaN metal-2DEG tunnel junction field-effect transistor (TJ-FET) is proposed and experimentally demonstrated in this work. The TJ-FET, when realized in AlGaN/GaN HEMT structure, delivers desirable features including normally-off operation (Vth = + 1.35 V), low leakage current (~10 pA/mm) and high on/off current ratio (1010). A maximum ON-state drain current density as high as 320 mA/mm has been obtained. The leakage current is effectively suppressed by the source Schottky junction that is naturally reverse biased in the OFF-state. The threshold voltage controlling scheme of TJ-FET is also fundamentally different from that of the conventional HEMTs, adding another degree of…

Subjects/Keywords: Power transistors; Gallium nitride; Semiconductors – Materials

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Yuan, L. (2011). Process modeling and device technology of GaN normally-off power transistors. (Thesis). Hong Kong University of Science and Technology. Retrieved from https://doi.org/10.14711/thesis-b1146196 ; http://repository.ust.hk/ir/bitstream/1783.1-7195/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Yuan, Li. “Process modeling and device technology of GaN normally-off power transistors.” 2011. Thesis, Hong Kong University of Science and Technology. Accessed June 16, 2019. https://doi.org/10.14711/thesis-b1146196 ; http://repository.ust.hk/ir/bitstream/1783.1-7195/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Yuan, Li. “Process modeling and device technology of GaN normally-off power transistors.” 2011. Web. 16 Jun 2019.

Vancouver:

Yuan L. Process modeling and device technology of GaN normally-off power transistors. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2011. [cited 2019 Jun 16]. Available from: https://doi.org/10.14711/thesis-b1146196 ; http://repository.ust.hk/ir/bitstream/1783.1-7195/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Yuan L. Process modeling and device technology of GaN normally-off power transistors. [Thesis]. Hong Kong University of Science and Technology; 2011. Available from: https://doi.org/10.14711/thesis-b1146196 ; http://repository.ust.hk/ir/bitstream/1783.1-7195/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Hong Kong University of Science and Technology

20. Lu, Jun-yong. Mechanical characterization of GaN epitaxial thin films.

Degree: 2011, Hong Kong University of Science and Technology

URL: https://doi.org/10.14711/thesis-b1155692 ; http://repository.ust.hk/ir/bitstream/1783.1-7360/1/th_redirect.html

► In this work, epitaxial GaN thin films were mechanically characterized. Residual stresses of the films were systematically investigated with micro-Raman spectroscopy and their elastic-plastic properties… (more)

▼ In this work, epitaxial GaN thin films were mechanically characterized. Residual stresses of the films were systematically investigated with micro-Raman spectroscopy and their elastic-plastic properties were studied by conducting nanoindentation tests at temperatures of 23 °C, 100 °C, and 180 °C. A series of works were carried out to investigate the mechanical stress- or strain-induced change in Raman spectrum of the GaN films. A home-made four-point bending device allows us to in-situ measure the uniaxial stress- or strain-induced change in Raman spectrum. The phonon frequency shifts were observed in-situ under four-pint bending and the experimental data were analyzed successfully. The present work developed a state-of-the-art biaxial stress modulation method, which was aided with the microelectromechanical system (MEMS) patterning technique and finite element analysis, to examine more thoroughly the change in Raman spectrum of GaN films under biaxial stress or strain. Based on the fact that residual stress is relaxed in a coin-shaped island, and the smaller the island is, the much more severe the residual stress will be relieved, we fabricated coin-shaped islands on an originally stressed GaN film and had the island radius ranging from xx μm to xx μm to modulate the biaxial stress. With this approach, the phonon deformation potentials (PDPs) of GaN were accurately and reliably determined to be 3.43 cm-1/GPa and 2.34 cm-1/GPa for EH2 and A1 (LO) phonons, respectively. With the determined PDPs, the residual stresses in various GaN films were convincingly characterized with the micro-Raman mapping technique. The GaN thin films were also characterized mechanically by using the nanoindentation technique. The elastic modulus of the GaN films were evaluated at temperatures of 23 °C, 100 °C, and 180 °C with the “O-P method” on unloading curve and the Hertzian contact analysis on the initial stage of loading curve. The experimental results show that the reduced modulus of GaN decreased with temperature from around 240 GPa (23 °C) to around 140 GPa (180 ºC) according to the “O-P method”, or from 270 GPa (23 °C) to around 230 GPa (180 ºC) according to the Hertzian analysis. The results might suggest that the Hertzian analysis could produce more reliable results in spite of the thermal drift accumulated at a high temperature. This is because the Hertzian analysis uses the initial experimental data which suffer less influence from the thermal drift, while the unloading curve bears more influence from the thermal drift. This research investigated the first pop-in event systematically. The first pop-in event in force-displacement curves reflects the elastic-plastic deformation transition of GaN films. A large number of data on the first pop-in event allowed statistical analysis. Based on Schuh et al.’s model, the statistical analysis yielded the activation energy of 849.76±35.85 meV, the activation volume of 10.76±1.61 Å3 and the frequency factor of 4.23×1021 m-3s-1. The shear strength, defined as the critical maximum shear…

Subjects/Keywords: Thin films – Mechanical properties; Gallium nitride; Epitaxy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lu, J. (2011). Mechanical characterization of GaN epitaxial thin films. (Thesis). Hong Kong University of Science and Technology. Retrieved from https://doi.org/10.14711/thesis-b1155692 ; http://repository.ust.hk/ir/bitstream/1783.1-7360/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Lu, Jun-yong. “Mechanical characterization of GaN epitaxial thin films.” 2011. Thesis, Hong Kong University of Science and Technology. Accessed June 16, 2019. https://doi.org/10.14711/thesis-b1155692 ; http://repository.ust.hk/ir/bitstream/1783.1-7360/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Lu, Jun-yong. “Mechanical characterization of GaN epitaxial thin films.” 2011. Web. 16 Jun 2019.

Vancouver:

Lu J. Mechanical characterization of GaN epitaxial thin films. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2011. [cited 2019 Jun 16]. Available from: https://doi.org/10.14711/thesis-b1155692 ; http://repository.ust.hk/ir/bitstream/1783.1-7360/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Lu J. Mechanical characterization of GaN epitaxial thin films. [Thesis]. Hong Kong University of Science and Technology; 2011. Available from: https://doi.org/10.14711/thesis-b1155692 ; http://repository.ust.hk/ir/bitstream/1783.1-7360/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Hong Kong University of Science and Technology

21. Li, Baikui. Magnetotransport and optoelectronic characterizations of AlGaN/GaN heterostructures.

Degree: 2010, Hong Kong University of Science and Technology

URL: https://doi.org/10.14711/thesis-b1114674 ; http://repository.ust.hk/ir/bitstream/1783.1-6887/1/th_redirect.html

► Fluorine plasma (F-plasma) treatment technique can effectively incorporate F-atoms into the AlGaN barrier, depleting the two-dimensional electron gases (2DEG) in AlGaN/GaN high electron mobility transistors… (more)

▼ Fluorine plasma (F-plasma) treatment technique can effectively incorporate F-atoms into the AlGaN barrier, depleting the two-dimensional electron gases (2DEG) in AlGaN/GaN high electron mobility transistors (HEMT) and converting the device from depletion-mode to enhancement-mode. In this thesis, the effects of F-plasma treatment on the transport and optoelectronic properties of AlGaN/GaN heterostructures were studied. It was found that the F-related centers were deep electron traps, which dominated the 2DEG scattering mechanism in F-plasma treated AlGaN/GaN heterostructures. Gated Hall measurements revealed that both 2DEG density and mobility increased when positive gate voltage was applied. It was obtained that the photoionization energy of the F-related centers was about 1.85 eV, while the energy barrier for electron recapture by F-related centers was determined to be 0.624 eV. The configuration-coordinate diagram of F-related centers in AlGaN/GaN heterostructure was obtained. The effects of F-plasma treatment on the performance of AlGaN/GaN heterostructure based UV-photodetectors were also investigated. Transport behaviors of the Ni/Au-AlGaN/GaN Schottky diodes in bias range far beyond the turn-on voltage were studied for the first time. A second turn-on was observed in the current-voltage (I-V) characteristics. Electroluminescence (EL) corresponding to the bandedge emission from GaN layer was detected when applied bias was larger than the second turn-on voltage, indicating that the second turn-on in the I-V characteristics was due to the hole injection into GaN layer. A model based on the Fermi level depinning due to the interface states ionization by hot electrons was proposed to explain the observed second turn-on in transport behaviors and the corresponding electroluminescence characteristics. The effects of F-plasma treatment on the transport as well as the EL behaviors of the Ni/Au-AlGaN/GaN Schottky diode were also investigated. It was found that the F-related deep centers in AlGaN barrier could assist the hole injection processes through hopping conduction.

Subjects/Keywords: Gallium nitride – Electric properties; Plasma chemistry; Heterostructures

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Li, B. (2010). Magnetotransport and optoelectronic characterizations of AlGaN/GaN heterostructures. (Thesis). Hong Kong University of Science and Technology. Retrieved from https://doi.org/10.14711/thesis-b1114674 ; http://repository.ust.hk/ir/bitstream/1783.1-6887/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Li, Baikui. “Magnetotransport and optoelectronic characterizations of AlGaN/GaN heterostructures.” 2010. Thesis, Hong Kong University of Science and Technology. Accessed June 16, 2019. https://doi.org/10.14711/thesis-b1114674 ; http://repository.ust.hk/ir/bitstream/1783.1-6887/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Li, Baikui. “Magnetotransport and optoelectronic characterizations of AlGaN/GaN heterostructures.” 2010. Web. 16 Jun 2019.

Vancouver:

Li B. Magnetotransport and optoelectronic characterizations of AlGaN/GaN heterostructures. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2010. [cited 2019 Jun 16]. Available from: https://doi.org/10.14711/thesis-b1114674 ; http://repository.ust.hk/ir/bitstream/1783.1-6887/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Li B. Magnetotransport and optoelectronic characterizations of AlGaN/GaN heterostructures. [Thesis]. Hong Kong University of Science and Technology; 2010. Available from: https://doi.org/10.14711/thesis-b1114674 ; http://repository.ust.hk/ir/bitstream/1783.1-6887/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Hong Kong University of Science and Technology

22. Zou, Xinbo. Growth, Fabrication and characterization of InGaN/GaN-based blue, green and yellow LEDs on Si with nanotechnology.

Degree: 2013, Hong Kong University of Science and Technology

URL: https://doi.org/10.14711/thesis-b1214705 ; http://repository.ust.hk/ir/bitstream/1783.1-8142/1/th_redirect.html

► InGaN/GaN-based light emitting diodes (LEDs) grown on Si have generated intensiveresearch interest due to silicon’s low cost, large size availability and good thermal conductivity. However,… (more)

▼ InGaN/GaN-based light emitting diodes (LEDs) grown on Si have generated intensiveresearch interest due to silicon’s low cost, large size availability and good thermal conductivity. However, GaN grown on Si normally suffers from large dislocation density and tensile stress due to the huge mismatch in the lattice constant and thermal expansion coefficient between GaN and Si. This thesis focuses on developing high-quality and crack-free InGaN/GaN-based blue, green and yellow LEDs with embedded SiO2 nanorods. GaN buffers were firstly optimized using a source flow ratio modulation method and an AlN/AlGaN superlattice interlayer. After optimization, crystalline quality, surface morphology and stress status were all improved. Moreover, light output power (LOP) was improved by 66% for InGaN/GaN blue LEDs. To further enhance the internal and external quantum efficiencies, high density SiO2 nanorods with an average diameter of less than 400 nm were fabricated on 2 μm thick GaN buffers and embedded into LED structures through nanoscale epitaxial lateral overgrowth. Two simple and non-lithographic methods for SiO2 nanorod fabrication were developed and compared in this work. With SiO2 nanorods surface coverage of 30%, 5 μm thick crack-free InGaN/GaN-based blue LEDs were grown with smooth surfaces. The LOP was raised by 40% compared to those without nanocomponents. The LED structures with embedded SiO2 nanorods were also extended to emit longer wavelength to fill the “green gap”. For 505 nm green LEDs, the optical power was as high as 0.65 mW at 20 mA. Moreover, for the first time, yellow InGaN/GaN MQW LEDs on Si substrates were demonstrated whose LOP and peak wavelength were 31 μW and 565 nm at 20 mA current injection. Low temperature characteristics of green and yellow LEDs were also described and discussed. In the last section of this thesis, a method to remove light absorptive Si substrates and fabricate vertical LEDs was described, in which the LOP was enhanced by 30% over planar LEDs on Si.

Subjects/Keywords: Light emitting diodes; Nanostructured materials; Gallium nitride

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zou, X. (2013). Growth, Fabrication and characterization of InGaN/GaN-based blue, green and yellow LEDs on Si with nanotechnology. (Thesis). Hong Kong University of Science and Technology. Retrieved from https://doi.org/10.14711/thesis-b1214705 ; http://repository.ust.hk/ir/bitstream/1783.1-8142/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zou, Xinbo. “Growth, Fabrication and characterization of InGaN/GaN-based blue, green and yellow LEDs on Si with nanotechnology.” 2013. Thesis, Hong Kong University of Science and Technology. Accessed June 16, 2019. https://doi.org/10.14711/thesis-b1214705 ; http://repository.ust.hk/ir/bitstream/1783.1-8142/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zou, Xinbo. “Growth, Fabrication and characterization of InGaN/GaN-based blue, green and yellow LEDs on Si with nanotechnology.” 2013. Web. 16 Jun 2019.

Vancouver:

Zou X. Growth, Fabrication and characterization of InGaN/GaN-based blue, green and yellow LEDs on Si with nanotechnology. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2013. [cited 2019 Jun 16]. Available from: https://doi.org/10.14711/thesis-b1214705 ; http://repository.ust.hk/ir/bitstream/1783.1-8142/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zou X. Growth, Fabrication and characterization of InGaN/GaN-based blue, green and yellow LEDs on Si with nanotechnology. [Thesis]. Hong Kong University of Science and Technology; 2013. Available from: https://doi.org/10.14711/thesis-b1214705 ; http://repository.ust.hk/ir/bitstream/1783.1-8142/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Hong Kong

23. Wang, Jun. Optical properties of graphene/GaN hybrid structure.

Degree: M. Phil., 2014, University of Hong Kong

URL: Wang, J. [王俊]. (2014). Optical properties of graphene/GaN hybrid structure. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5223998 ; http://dx.doi.org/10.5353/th_b5223998 ; http://hdl.handle.net/10722/206660

►

Optical properties of graphene/GaN hybrid structure were investigated by using a variety of optical spectroscopy techniques including low-temperature photoluminescence (PL) spectroscopy, time-resolved PL (TRPL) spectroscopy,… (more)

Subjects/Keywords: Graphene - Optical properties; Gallium nitride - Optical properties

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APA (6^th Edition):

Wang, J. (2014). Optical properties of graphene/GaN hybrid structure. (Masters Thesis). University of Hong Kong. Retrieved from Wang, J. [王俊]. (2014). Optical properties of graphene/GaN hybrid structure. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5223998 ; http://dx.doi.org/10.5353/th_b5223998 ; http://hdl.handle.net/10722/206660

Chicago Manual of Style (16^th Edition):

Wang, Jun. “Optical properties of graphene/GaN hybrid structure.” 2014. Masters Thesis, University of Hong Kong. Accessed June 16, 2019. Wang, J. [王俊]. (2014). Optical properties of graphene/GaN hybrid structure. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5223998 ; http://dx.doi.org/10.5353/th_b5223998 ; http://hdl.handle.net/10722/206660.

MLA Handbook (7^th Edition):

Wang, Jun. “Optical properties of graphene/GaN hybrid structure.” 2014. Web. 16 Jun 2019.

Vancouver:

Wang J. Optical properties of graphene/GaN hybrid structure. [Internet] [Masters thesis]. University of Hong Kong; 2014. [cited 2019 Jun 16]. Available from: Wang, J. [王俊]. (2014). Optical properties of graphene/GaN hybrid structure. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5223998 ; http://dx.doi.org/10.5353/th_b5223998 ; http://hdl.handle.net/10722/206660.

Council of Science Editors:

Wang J. Optical properties of graphene/GaN hybrid structure. [Masters Thesis]. University of Hong Kong; 2014. Available from: Wang, J. [王俊]. (2014). Optical properties of graphene/GaN hybrid structure. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5223998 ; http://dx.doi.org/10.5353/th_b5223998 ; http://hdl.handle.net/10722/206660

University of Hong Kong

24. 李攜曦.; Li, Kwai-hei. Nanostructuring for nitride light-emitting diodes and opticalcavities.

Degree: PhD, 2013, University of Hong Kong

URL: Li, K. [李攜曦]. (2013). Nanostructuring for nitride light-emitting diodes and optical cavities. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5043439 ; http://dx.doi.org/10.5353/th_b5043439 ; http://hdl.handle.net/10722/184252

► The group of III-V semiconductors is emerging as highly attractive materials for a wide range of applications, particularly the gallium nitride family of alloys. Undoubtedly,… (more)

▼ The group of III-V semiconductors is emerging as highly attractive materials for a wide range of applications, particularly the gallium nitride family of alloys. Undoubtedly, the development of nitride-based light-emitting diodes (LEDs) and laser diodes (LDs) represented a quantum leap in the advancement of optoelectronics. The timely arrival of InGaN blue LEDs enable full-color mixing with existing red and green LEDs based on AlInGaP and GaP alloys respectively, promoting the progress of solid-state lighting and displays, while the blue-violet LDs has revolutionized high-density optical data storage in the form of blu-ray. Extensive research efforts have been conducted on producing energy-efficient and highly reliable LEDs and LDs in the past decade. Amongst potential strategies, nanotechnology promises to offer significant boosts to device performances. Nano-structure on a scale of wavelength of light exhibits prominent effects on the propagation behavior of photons. However, the formation of well-defined nanostructure relies heavily on processing techniques. Although e-beam lithography enables precise direct-writing of nano-patterns, high equipment cost and time-consuming processes make mass production impractical. On the other hand, the technique of nanosphere lithography (NSL) as adopted in the work reported in this thesis is a practical alternative approach. Uniform spheres acting as etch masks are capable of self-assembling into hexagonal close-packed arrays. The resultant nanopillar array serves as the photonic crystals (PhCs) extracting guided light while the individual pillars may act as circular cavities supporting the whispering gallery (WG) mode. Due to total internal reflections at the GaN-ambient interface with high refractive index contrast, low extraction efficiency is one of the major bottlenecks for LEDs. To assist with light extraction, the LED surfaces are textured via NSL to form PhC structures. The feature dimensions of the resultant patterns are scalable according to the diameter of nanospheres used. Such ordered closedpacked arrays are capable of promoting light extraction via the dispersion and diffraction properties of PhCs. To extend the functionality of sphere-patterned arrays, a dimension-adjusting procedure is developed to realize photonic bandgap (PBG) structures. Finite spacing between individual spheres is introduced, resulting in air-spaced nano-pillar PhCs structure with a wavelength-tunable PBG. Distinguished from typical PhCs in the form of air-holes or pillars, a clovershaped structure with a wide PBG is fabricated by dual-step NSL. The PBG structures have been exploited for suppressing lateral wave-guiding and possibly redirecting a significant proportion of trapped photons for extraction. Among various lasing mechanisms in nitride-based material, the whispering gallery mode based on cylindrical resonators is a promising candidate with attractive properties of intrinsically high Q factor, low lasing threshold and simple fabrication process. Since multiple-modes lasing from… Advisors/Committee Members: Choi, HW, Wu, FF.

Subjects/Keywords: Gallium nitride.; Light emitting diodes.; Nanostructured materials.

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APA (6^th Edition):

李攜曦.; Li, K. (2013). Nanostructuring for nitride light-emitting diodes and opticalcavities. (Doctoral Dissertation). University of Hong Kong. Retrieved from Li, K. [李攜曦]. (2013). Nanostructuring for nitride light-emitting diodes and optical cavities. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5043439 ; http://dx.doi.org/10.5353/th_b5043439 ; http://hdl.handle.net/10722/184252

Chicago Manual of Style (16^th Edition):

李攜曦.; Li, Kwai-hei. “Nanostructuring for nitride light-emitting diodes and opticalcavities.” 2013. Doctoral Dissertation, University of Hong Kong. Accessed June 16, 2019. Li, K. [李攜曦]. (2013). Nanostructuring for nitride light-emitting diodes and optical cavities. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5043439 ; http://dx.doi.org/10.5353/th_b5043439 ; http://hdl.handle.net/10722/184252.

MLA Handbook (7^th Edition):

李攜曦.; Li, Kwai-hei. “Nanostructuring for nitride light-emitting diodes and opticalcavities.” 2013. Web. 16 Jun 2019.

Vancouver:

李攜曦.; Li K. Nanostructuring for nitride light-emitting diodes and opticalcavities. [Internet] [Doctoral dissertation]. University of Hong Kong; 2013. [cited 2019 Jun 16]. Available from: Li, K. [李攜曦]. (2013). Nanostructuring for nitride light-emitting diodes and optical cavities. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5043439 ; http://dx.doi.org/10.5353/th_b5043439 ; http://hdl.handle.net/10722/184252.

Council of Science Editors:

李攜曦.; Li K. Nanostructuring for nitride light-emitting diodes and opticalcavities. [Doctoral Dissertation]. University of Hong Kong; 2013. Available from: Li, K. [李攜曦]. (2013). Nanostructuring for nitride light-emitting diodes and optical cavities. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5043439 ; http://dx.doi.org/10.5353/th_b5043439 ; http://hdl.handle.net/10722/184252

University of Hong Kong

25. Bao, Wei. Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars.

Degree: M. Phil., 2012, University of Hong Kong

URL: Bao, W. [包伟]. (2012). Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5060580 ; http://dx.doi.org/10.5353/th_b5060580 ; http://hdl.handle.net/10722/188753

►

In this thesis, the carrier localization effect, the quantum confinement Stark effect (QCSE) and nonlinear optical properties of the as-grown InGaN/GaN multiple-quantum-wells (MQWs) structure and… (more)

Subjects/Keywords: Gallium nitride - Optical properties.; Quantum wells.; Photoluminescence.

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APA (6^th Edition):

Bao, W. (2012). Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. (Masters Thesis). University of Hong Kong. Retrieved from Bao, W. [包伟]. (2012). Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5060580 ; http://dx.doi.org/10.5353/th_b5060580 ; http://hdl.handle.net/10722/188753

Chicago Manual of Style (16^th Edition):

Bao, Wei. “Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars.” 2012. Masters Thesis, University of Hong Kong. Accessed June 16, 2019. Bao, W. [包伟]. (2012). Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5060580 ; http://dx.doi.org/10.5353/th_b5060580 ; http://hdl.handle.net/10722/188753.

MLA Handbook (7^th Edition):

Bao, Wei. “Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars.” 2012. Web. 16 Jun 2019.

Vancouver:

Bao W. Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. [Internet] [Masters thesis]. University of Hong Kong; 2012. [cited 2019 Jun 16]. Available from: Bao, W. [包伟]. (2012). Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5060580 ; http://dx.doi.org/10.5353/th_b5060580 ; http://hdl.handle.net/10722/188753.

Council of Science Editors:

Bao W. Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. [Masters Thesis]. University of Hong Kong; 2012. Available from: Bao, W. [包伟]. (2012). Photoluminescence study of InGaN/GaN multiple-quantum-wells nanopillars. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5060580 ; http://dx.doi.org/10.5353/th_b5060580 ; http://hdl.handle.net/10722/188753

University of Manchester

26. Christian, George. Photoluminescence Studies of InGaN/GaN Quantum Well Structures.

Degree: 2018, University of Manchester

URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:317549

► In this thesis, optical studies of c-plane InGaN/GaN quantum well (QW) structures are presented. The effects of a Si-doped underlayer (UL) on the optical properties… (more)

▼ In this thesis, optical studies of c-plane InGaN/GaN quantum well (QW) structures are presented. The effects of a Si-doped underlayer (UL) on the optical properties of multiple quantum well (MQW) structures are investigated. The QW photoluminescence (PL) emission peak energy and radiative recombination rate decrease and increase respectively with increasing number of QWs. These observations are attributed to the increasing net electric field across the MQW structure as the strength of the surface polarisation field, which acts in the opposite sense to the piezoelectric polarisation fields across the QWs, reduces with increasing distance of the UL from the sample surface. This leads to a reduction in the electron-hole recombination energy and wavefunction overlap. It is also shown that the internal quantum efficiency of the MQW structures may decrease with increasing number of QWs due to the reducing radiative recombination rate, which could indicate that carrier losses due to thermionic emission or interface recombination are mitigated by the inclusion of an UL. Optical studies of single QW structures containing Si-doped ULs with different net electric fields across the QW are presented. The net electric field across the QW is changed by varying the thickness of the GaN cap layer. The full width at half maximum of the emission peak increases with increasing net electric field across the QW. This is attributed to the increasing variation in electron ground state energies due to the role of the electric field in the localisation of electrons at quantum well width fluctuations. For one sample, a smaller Huang-Rhys factor compared to the rest of the samples is calculated. The non-exponential PL decays detected on the low energy side of the QW emission peak from this sample are also of a different shape to the other PL decays detected at all energies for the other samples. This may be due to the reversal of the net electric field across these QW regions. Observations of a broad emission band on the high energy side of single QW structures at high excited carrier densities are presented. This band occurs in the carrier density regime at which the efficiency droop is observed. The emission band is attributed to higher energy weakly localised or delocalised electron and hole states that are populated following the saturation of the localised ground states. PL decay curves detected across this emission band exhibit plateaus where the PL intensity remains constant until the higher energy emission has decayed. These are similar to decays observed in semiconductor quantum dots, which are characteristic of Pauli state blocking. Advisors/Committee Members: BINKS, DAVID DJ, Dawson, Philip, Binks, David.

Subjects/Keywords: photoluminescence; gallium nitride; nitrides; quantum well; semiconductor

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APA (6^th Edition):

Christian, G. (2018). Photoluminescence Studies of InGaN/GaN Quantum Well Structures. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:317549

Chicago Manual of Style (16^th Edition):

Christian, George. “Photoluminescence Studies of InGaN/GaN Quantum Well Structures.” 2018. Doctoral Dissertation, University of Manchester. Accessed June 16, 2019. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:317549.

MLA Handbook (7^th Edition):

Christian, George. “Photoluminescence Studies of InGaN/GaN Quantum Well Structures.” 2018. Web. 16 Jun 2019.

Vancouver:

Christian G. Photoluminescence Studies of InGaN/GaN Quantum Well Structures. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2019 Jun 16]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:317549.

Council of Science Editors:

Christian G. Photoluminescence Studies of InGaN/GaN Quantum Well Structures. [Doctoral Dissertation]. University of Manchester; 2018. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:317549

Rochester Institute of Technology

27. Hartensveld, Matthew. Optimization of Dry and Wet GaN Etching to Form High Aspect Ratio Nanowires.

Degree: MS, School of Chemistry and Materials Science (COS), 2018, Rochester Institute of Technology

URL: https://scholarworks.rit.edu/theses/9835

► Nanowire devices are emerging as the replacement technology to planar devices, such as Light Emitting Diodes (LEDs) and Field Effect Transistors (FETs), due to… (more)

Subjects/Keywords: Etching; Gallium nitride; GaN; KOH; Nanowire; Nanowires

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APA (6^th Edition):

Hartensveld, M. (2018). Optimization of Dry and Wet GaN Etching to Form High Aspect Ratio Nanowires. (Masters Thesis). Rochester Institute of Technology. Retrieved from https://scholarworks.rit.edu/theses/9835

Chicago Manual of Style (16^th Edition):

Hartensveld, Matthew. “Optimization of Dry and Wet GaN Etching to Form High Aspect Ratio Nanowires.” 2018. Masters Thesis, Rochester Institute of Technology. Accessed June 16, 2019. https://scholarworks.rit.edu/theses/9835.

MLA Handbook (7^th Edition):

Hartensveld, Matthew. “Optimization of Dry and Wet GaN Etching to Form High Aspect Ratio Nanowires.” 2018. Web. 16 Jun 2019.

Vancouver:

Hartensveld M. Optimization of Dry and Wet GaN Etching to Form High Aspect Ratio Nanowires. [Internet] [Masters thesis]. Rochester Institute of Technology; 2018. [cited 2019 Jun 16]. Available from: https://scholarworks.rit.edu/theses/9835.

Council of Science Editors:

Hartensveld M. Optimization of Dry and Wet GaN Etching to Form High Aspect Ratio Nanowires. [Masters Thesis]. Rochester Institute of Technology; 2018. Available from: https://scholarworks.rit.edu/theses/9835

King Abdullah University of Science and Technology

28. Ibrahim, Youssef H. Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices.

Degree: 2013, King Abdullah University of Science and Technology

URL: http://hdl.handle.net/10754/292971

► Group III-nitride semiconductors possess unique properties, which make them versatile materials for suiting many applications. Structuring vertical and exceptionally smooth GaN profiles is crucial for… (more)

Subjects/Keywords: Gallium; Nitride; Inductively; Coupled; Plasma; Facets

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APA (6^th Edition):

Ibrahim, Y. H. (2013). Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices. (Thesis). King Abdullah University of Science and Technology. Retrieved from http://hdl.handle.net/10754/292971

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Ibrahim, Youssef H. “Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices.” 2013. Thesis, King Abdullah University of Science and Technology. Accessed June 16, 2019. http://hdl.handle.net/10754/292971.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Ibrahim, Youssef H. “Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices.” 2013. Web. 16 Jun 2019.

Vancouver:

Ibrahim YH. Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices. [Internet] [Thesis]. King Abdullah University of Science and Technology; 2013. [cited 2019 Jun 16]. Available from: http://hdl.handle.net/10754/292971.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Ibrahim YH. Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices. [Thesis]. King Abdullah University of Science and Technology; 2013. Available from: http://hdl.handle.net/10754/292971

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

29. Johansson, Linus. Evaluation of graphene as a transparent electrode in GaN-based LEDs by PECVD synthesis of graphene directly on GaN.

Degree: Physics, 2016, Umeå University

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120731

► A transparent conductive electrode (TCE) is an important component in many of our modern optoelectronic devices like photovoltaics, light emitting diodes and touch screens.… (more)

▼ A transparent conductive electrode (TCE) is an important component in many of our modern optoelectronic devices like photovoltaics, light emitting diodes and touch screens. These devices require good current injection and spreading as well as a high transparency. In this thesis we explore the use of graphene as an alternative to the current widely used indium tin oxide (ITO) as TCE in gallium nitride (GaN) based light emitting diodes (LEDs). Monolayer crystalline graphene can be produced on copper foils using chemical vapor deposition (CVD), where metals (especially copper) has a catalysing effect on the formation of graphene. However, transfer of graphene from copper foils is not suitable for an industrial scale and it results in a poor contact with the target substrate. We investigate the possibility of directly integrating graphene on GaN-based LEDs by using plasma-enhanced chemical vapor deposition (PECVD). We try to obtain the optimal conditions under these catalyst-free circumstances and propose a recipe adapted for the setup that we used. We will also study ideas of using a metal (we tried copper and nickel) to assist the direct growth that could help to increase the fraction of sp² carbon bonds and reduce the sheet resistance. The metals are evaporated onto our samples either before or after we grow a carbon film to either assist the growth or rearrange the carbon respectively. The focus was not on trying to optimize the conditions for one metal treatment but rather to briefly explore multiple methods to find a suitable path for further studies. The direct grown pristine carbon films shows indications from Raman measurements of being nanocrystalline graphene with a sheet resistance ranging from about 20-50 kΩ/sq having a transmittance of approximately 96 % at 550 nm. A transmittance at this level is closely related to the value of an ideal monolayer graphene, which indicates that our carbon films could be close to one atom in thickness while being visually homogeneous and complete in coverage. Due to the use of a temperature close to the melting point of copper we struggled to keep the assisting copper from evaporating too fast or staying homogeneous after the treatment. Nickel has a higher melting temperature, but it appears as if this metal might be diffusing into the GaN substrate which changes the properties of both the GaN and carbon film. Even though the metal treatments that we tested did not provide any noticeable improvements, there is need for further investigations to obtain suitable treatment conditions. We suggest that the treatments involving copper are a more promising path to pursue as nickel seem to cause unavoidable intermixing problems.

Subjects/Keywords: PECVD; graphene; transparent electrode; gallium nitride; LED

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APA (6^th Edition):

Johansson, L. (2016). Evaluation of graphene as a transparent electrode in GaN-based LEDs by PECVD synthesis of graphene directly on GaN. (Thesis). Umeå University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120731

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Johansson, Linus. “Evaluation of graphene as a transparent electrode in GaN-based LEDs by PECVD synthesis of graphene directly on GaN.” 2016. Thesis, Umeå University. Accessed June 16, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120731.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Johansson, Linus. “Evaluation of graphene as a transparent electrode in GaN-based LEDs by PECVD synthesis of graphene directly on GaN.” 2016. Web. 16 Jun 2019.

Vancouver:

Johansson L. Evaluation of graphene as a transparent electrode in GaN-based LEDs by PECVD synthesis of graphene directly on GaN. [Internet] [Thesis]. Umeå University; 2016. [cited 2019 Jun 16]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120731.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Johansson L. Evaluation of graphene as a transparent electrode in GaN-based LEDs by PECVD synthesis of graphene directly on GaN. [Thesis]. Umeå University; 2016. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120731

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Tennessee – Knoxville

30. Bouler, Douglas Wayne, III. GAN-BASED POINT-OF-LOAD CONVERTERS FOR DATA CENTER APPLICATIONS.

Degree: MS, Electrical Engineering, 2018, University of Tennessee – Knoxville

URL: https://trace.tennessee.edu/utk_gradthes/5341

► The growth of the information technology sector has increased demand for high-density, high-efficiency point-of-load (POL) converters. As industry continues to demand an increase in server… (more)

Subjects/Keywords: Gallium-Nitride; GaN; POL; power density

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APA (6^th Edition):

Bouler, Douglas Wayne, I. (2018). GAN-BASED POINT-OF-LOAD CONVERTERS FOR DATA CENTER APPLICATIONS. (Thesis). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_gradthes/5341

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Bouler, Douglas Wayne, III. “GAN-BASED POINT-OF-LOAD CONVERTERS FOR DATA CENTER APPLICATIONS.” 2018. Thesis, University of Tennessee – Knoxville. Accessed June 16, 2019. https://trace.tennessee.edu/utk_gradthes/5341.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Bouler, Douglas Wayne, III. “GAN-BASED POINT-OF-LOAD CONVERTERS FOR DATA CENTER APPLICATIONS.” 2018. Web. 16 Jun 2019.

Vancouver:

Bouler, Douglas Wayne I. GAN-BASED POINT-OF-LOAD CONVERTERS FOR DATA CENTER APPLICATIONS. [Internet] [Thesis]. University of Tennessee – Knoxville; 2018. [cited 2019 Jun 16]. Available from: https://trace.tennessee.edu/utk_gradthes/5341.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bouler, Douglas Wayne I. GAN-BASED POINT-OF-LOAD CONVERTERS FOR DATA CENTER APPLICATIONS. [Thesis]. University of Tennessee – Knoxville; 2018. Available from: https://trace.tennessee.edu/utk_gradthes/5341

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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Open Access Theses and Dissertations